Network physical link (PHY) switch system

ABSTRACT

One example includes network physical link (PHY) switch system. The system includes a multiplexer to output a first of a plurality of data streams that are input to a PHY device in response to a first state of a selection signal. The system also includes a data detector that monitors the first data stream and provides a trigger signal in response to a predetermined condition associated with the first data stream. The system further includes a switching controller that provides the selection signal, and in response to a switching command signal indicating a command to switch from the first data stream to the second data stream, monitors the data detector for the trigger signal and changes the selection signal from the first state to a second state in response to receiving the trigger signal to switch to the second data stream of the plurality of data streams.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 61/833,597, filed Jun. 11, 2013, and entitled A DATAAWARE SMART PHY SWITCH FOR 10GBASE-KR, which is incorporated herein byreference in its entirety.

TECHNICAL FIELD

This disclosure relates generally to network systems, and morespecifically to a network physical link (PHY) switch system.

BACKGROUND

A variety of networks implement switching and/or routing as a means ofproviding an input data stream to one of several separate outputs todisseminate the input data stream to different devices on the network.Network data switching can be implemented on a variety of differenttypes of networks, such as Ethernet networks that operate via one of avariety of different transport media (e.g., optical fiber and/or copperor a different metal conductor, such as associated with a 10GBase-KREthernet). Due to the high-speed transfer of data across a network andto amount of data traffic on the network, it is desirable to implementswitching of an input data stream to an output of a routing device asquickly as possible. Rapid switching not only maintains high-speed datatransfer, but can also substantially mitigate corruption of data (e.g.,data packets) that are transmitted.

SUMMARY

One example includes network physical link (PHY) switch system. Thesystem includes a multiplexer configured to output a first data streamof a plurality of data streams that are input to a PHY device inresponse to a first state of a selection signal. The system alsoincludes a data detector configured to monitor the first data stream andto provide a trigger signal in response to an occurrence of apredetermined condition associated with the first data stream. Thesystem further includes a switching controller that provides theselection signal, and in response to a switching command signalindicating a command to switch from the first data stream to the seconddata stream, monitors the data detector for the trigger signal andchanges the selection signal from the first state to a second state inresponse to receiving the trigger signal to switch to the second datastream of the plurality of data streams.

Another embodiment includes a method for switching from a first datastream to a second data stream in a PHY device of a network device. Themethod includes providing a selection signal in a first state to selectthe first data stream that is input to the PHY device to be output froma multiplexer. The method also includes receiving a switching controlsignal that indicates a command to switch from the first data stream tothe second data stream. The method also includes monitoring an output ofa first-in-first-out (FIFO) buffer to detect a predetermined conditionassociated with the first data stream. The method also includesproviding a trigger signal in response to an occurrence of thepredetermined condition. The method further includes providing theselection signal in a second state to switch the input to the PHY devicefrom the first data stream to the second data stream to be output fromthe multiplexer.

Another embodiment includes crosspoint routing system comprising a PHYdevice. The PHY device includes a media access control (MAC) interfacecomprising a MAC interface output configured to transmit a MAC receivesignal corresponding to one of a MAC transmit signal and a PHY receivesignal to a MAC device via a MAC interface switch. The MAC interfacefurther includes a MAC interface input configured to receive the MACtransmit signal from the MAC device. The PHY device further includes aPMD interface comprising a PMD interface output configured to transmit aPHY transmit signal corresponding to one of the MAC transmit signal andthe PHY receive signal to a backplane via a PMD interface switch. ThePMD interface further includes a PMD interface input configured toreceive the PHY receive signal from the backplane.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a network PHY switch system.

FIG. 2 illustrates another example of a network PHY switch system.

FIG. 3 illustrates an example of a routing device.

FIG. 4 illustrates an example of a crosspoint routing system.

FIG. 5 illustrates an example of a PHY device.

FIG. 6 illustrates yet another example of a network PHY switch system.

FIG. 7 illustrates a further example of a network PHY switch system.

FIG. 8 illustrates an example of a method for switching from a firstdata stream to a second data stream in a PHY device of a network device.

DETAILED DESCRIPTION

This disclosure relates generally to network systems, and morespecifically to a network physical link (PHY) switch system. A networkPHY switch system can be implemented in a number of networkapplications, such as Ethernet (e.g., 10GBase-KR Ethernet). The networkPHY switch system can be implemented in a PHY device to implementswitching from a first data stream of a plurality of data streams to asecond data stream of the plurality of data streams. The plurality ofdata streams can include inputs to the PHY device from a media accesscontrol (MAC) device and/or inputs to the PHY device from an associatedbackplane, such as in a crosspoint switching router. For example, thecrosspoint switching router can include a plurality of ports, with eachport including a MAC device and a PHY device. The PHY device can includea network PHY switch system in each of a plurality of outputs toimplement PHY switching of the inputs to the PHY device according to oneof a plurality of switching modes (e.g., mission mode, crosspoint mode,and/or retime mode).

As an example, the network PHY switch system can include a multiplexerconfigured to receive each of the plurality of data streams, such ascorresponding to each of a plurality of inputs to the associated PHYdevice. The multiplexer can provide a given one of the data streams atan output based on a first state of a selection signal. The network PHYswitch system can also include a data detector that is configured tomonitor the data that is output from the multiplexer. For example, thedata detector can be configured to monitor the data provided from themultiplexer at an output of a first-in-first-out (FIFO) buffer, such asconfigured to implement clock time compensation (CTC). The data detectorcan be configured to generate a trigger signal in response to detectinga predetermined condition associated with the data stream, such as anend of packet condition. That is, the PHY switch system can be dataaware based on monitoring the data. The network PHY switch system canalso include a switch controller that can generate the selection signal.For example, the switch controller can receive a switching controlsignal that indicates a command to switch from a first data stream to asecond data stream. The switch controller can thus be configured tochange the state of the selection signal in response to the triggersignal based on the switching control signal necessitating a change fromthe first data stream to the second data stream. As an example, thenetwork PHY switch can also include a data mask component that isconfigured to replace the monitored data stream with dummy data (e.g.,idle data or idle pairs) in response to the trigger signal, such asuntil the data detector detects a beginning of a packet of the seconddata stream. Therefore, because the switch controller only changes thestate of the selection signal in response to the trigger signal, andthus based on the predetermined condition (e.g., end of a packet),packet corruption, which typically occurs in response to switching to adifferent data source, can be mitigated.

FIG. 1 illustrates an example of a network physical link (PHY) switchsystem 10. The network PHY switch system 10 can be implemented in avariety of network applications that require routing of data streamsfrom disparate data sources. The network PHY switch system 10 can beimplemented in a PHY device (e.g., an integrated circuit (IC)), such asin a router (e.g., a crosspoint routing system). As an example, thenetwork PHY switch system 10 can be implemented in an Ethernet networksystem, such as in a 10GBase-KR network router.

In the example of FIG. 1, the network PHY switch system 10 is configuredto provide an output data stream OUT_(sw) that corresponds to a givenone of a plurality X of input data streams, demonstrated in the exampleof FIG. 1 as IN₁ through IN_(X), where X is a positive integer. Theselection of the given one of the input data streams IN₁ through IN_(X)can be set by a switching control signal SW_(CTL), such as provided froman external circuit or device (e.g., a management data input/output(MDIO) device).

In the example of FIG. 1, the network PHY switch system 10 includes amultiplexer 12, a data detector 14, and a switching controller 16. Themultiplexer 12 is configured to receive the input data streams IN₁through IN_(X) and to provide a given one of the input data streams IN₁through IN_(X) at an output based on the switching controller 16 (e.g.,based on a state of a selection signal provided by the switchingcontroller 16). As an example, the switching controller 16 can controlwhich of the input data streams IN₁ through IN_(X) in response to theswitching control signal SW_(CTL). The data detector 14 is configured tomonitor the given one of the data streams IN₁ through IN_(X) that isprovided at the output of the multiplexer 12, and can provide anindication to the switching controller 16 of the occurrence of apredetermined condition associated with the given one of the datastreams IN₁ through IN_(X) at the output of the multiplexer 12. As anexample, the indication can be a trigger signal that is indicative ofthe predetermined condition. For example, the predetermined conditioncan correspond to an end of a packet of the first of the input datastreams IN₁ through IN_(X), and/or can correspond to one of a pluralityof other types of conditions associated with the given one of the datastreams IN₁ through IN_(X). Thus, the switching controller 16 can beprogrammed to switch from a first of the input data streams IN₁ throughIN_(X) to a second of the input data streams IN₁ through IN_(X) based onthe predetermined condition, such as to mitigate packet corruption ofthe data in the output data stream OUT_(SW).

As an example, the switching controller 16 can provide a selectionsignal at a first state to the multiplexer 12 to provide a first of theinput data streams IN₁ through IN_(X) at the output of the multiplexer12, and thus as the output data stream OUT_(SW). The switching controlsignal SW_(CTL) can indicate a command to switch from the first of theinput data streams IN₁ through IN_(X) to a second of the input datastreams IN₁ through IN_(X). In response, the data detector 14 canmonitor the first of the input data streams IN₁ through IN_(X) at theoutput of the multiplexer 12 for the predetermined condition (e.g., anend of a packet of the first of the input data streams IN₁ throughIN_(X) or a variety of other predetermined data patterns or conditions).In response to detecting the predetermined condition, the data detector14 can provide indication of the occurrence of the predeterminedcondition (e.g., via a trigger signal) to the switching controller 16.As a result of switching in response to the predetermined condition, thenetwork PHY switch system provides switching in a manner that isdata-aware, such as to preserve the integrity of the data that isprovided as the output data stream OUT_(SW). Thus, in response to theindication of the occurrence of the predetermined condition, theswitching controller 16 can change the state of the selection signal,thus switching the multiplexer 12 from the first of the input datastreams IN₁ through IN_(X) to another of the input data streams IN₁through IN_(X) to be provided at the output of the multiplexer 12,namely, as the output data stream OUT_(SW).

FIG. 2 illustrates another example of a network PHY switch system 50.The network PHY switch system 50 can be implemented in a variety ofnetwork applications that require routing of data streams from disparatedata sources. The network PHY switch system 50 can be implemented in aPHY device such as in a crosspoint routing system. As an example, thenetwork PHY switch system 50 can be implemented in an Ethernet networksystem, such as in a 10GBase-KR network router, such as residing between10GBit Media Independent Interface (XGMII) and a KR physical codingsublayer (PCS) interface. As an example, the network PHY switch system50 can correspond to the network PHY switch system 10 in the example ofFIG. 1.

In the example of FIG. 2, the network PHY switch system 50 is configuredto provide an output data stream OUT_(SW) that corresponds to a givenone of the plurality of input data streams IN₁ through IN_(X) that areprovided to a multiplexer 52. As an example, the input data streams IN₁through IN_(X) can correspond to inputs provided from a physical mediumdependent (PMD) interface and/or a media access control (MAC) interfacein the associated PHY device. The selection of the given one of theinput data streams IN₁ through IN_(X) via the multiplexer 52 can be setby a switching controller 54 in response to a switching control signalSW_(CTL), such as provided from an external circuit or device (e.g., amanagement data input/output (MDIO) device). In the example of FIG. 2,the switching controller 54 provides a selection signal SEL having astate that corresponds to a given one of the input data streams IN₁through IN_(X) that is to be provided as a data stream OUT_(M) at anoutput of the multiplexer 52. The data stream OUT_(M) is provided to aclock time compensation (CTC) first-in-first-out (FIFO) buffer 56 thatis configured to queue the data stream OUT_(M) and to provide the datastream OUT_(M) as a clock time compensated output stream OUT_(F). Forexample, the input data streams IN₁ through IN_(X) can be provided inasynchronous clock domains, such that the CTC FIFO 56 can provide theclock time compensation to provide the clock time compensated datastream OUT_(F) substantially continuously. Additionally, because theasynchronous input data streams IN₁ through IN_(X) are multiplexed viathe multiplexer 52 upstream of the CTC FIFO 56, the network PHY switchsystem 50 can be implemented in a more compact circuit design, asopposed to typical switching systems that implement non-PHY deviceswitching.

The clock time compensated data stream OUT_(F) is provided to a datadetector 58. The data detector 58 is configured to monitor the clocktime compensated data stream OUT_(F) to provide an indication to theswitching controller 54 of the occurrence of a predetermined conditionassociated with the clock time compensated data stream OUT_(F). As anexample, the predetermined condition can correspond to an end of apacket of the clock time compensated data stream OUT_(F), can correspondto a programmable character or ordered set, or can correspond to any ofa variety of data and/or data pattern in the clock time compensated datastream OUT_(F). In the example of FIG. 2, the data detector 58 isconfigured to provide a trigger signal TRG to the switching controller54 that is indicative of the predetermined condition. Thus, theswitching controller 54 is programmed to switch the state of theselection signal SEL from a first of the input data streams IN₁ throughIN_(X) to a second of the input data streams IN₁ through IN_(X) inresponse to the trigger signal TRG based on an indication of a switchfrom the first of the input data streams IN₁ through IN_(X) to thesecond of the input data streams IN₁ through IN_(X) provided by theswitching control signal SW_(CTL).

The network PHY switch system 50 also includes a data mask component 60that receives the clock time compensated data stream OUT_(F). The datamask component 60 can be configured, for example, as logic that isconfigured to replace the clock time compensated data stream OUT_(F)with dummy data DD that is provided by the switching controller 54 inresponse to the trigger signal TRG, and thus the switching from thefirst of the input data streams IN₁ through IN_(X) to the second of theinput data streams IN₁ through IN_(X) via the selection signal SEL. Asan example, the dummy data DD can correspond to predetermined idle dataor idle pairs (e.g., such as generated by the switching controller 54 orfrom an associated MDIO). Thus, in response to the indication of thepredetermined condition provided by the trigger signal TRG (e.g., end ofa packet), the data mask 60 can discard the data in the clock timecompensated data stream OUT_(F) subsequent to the predeterminedcondition and provide the output data stream OUT_(SW) as the dummy dataDD.

The data detector 58 can also be configured to provide a detectionsignal in response to detecting a predetermined condition associatedwith the clock time compensated data stream OUT_(F), such as associatedwith the corresponding second of the input data streams IN₁ throughIN_(X), via the trigger signal TRG. For example, the data detector 58can provide a detector output to deactivate the trigger signal TRG inresponse to detecting a beginning of the second of the input datastreams IN₁ through IN_(X) (e.g., a start of a first packet) in theclock time compensated data stream OUT_(F). In response, the switchingcontroller 54 can deactivate the data mask component 60, such that thedata mask component 60 no longer replaces the clock time compensateddata stream OUT_(F) with dummy data DD, but instead allows the clocktime compensated data stream OUT_(F) to pass through the data maskcomponent 60 as the output data stream OUT_(SW). As a result, based onthe switching controller 54 delaying switching of the first of the inputdata streams IN₁ through IN_(X) to the second of the input data streamsIN₁ through IN_(X) until the trigger signal TRG is provided, and thusuntil the predetermined condition has occurred and during which time theoutput data stream OUT_(SW) is provided as the dummy data DD, thenetwork PHY switch system 50 can substantially mitigate corruption ofthe output data stream OUT_(SW) that can result from the switchingbetween different streams. Additionally, because the switching isimplemented in a PHY device, as opposed to a MAC device, resources ofthe associated MAC device can be relegated to other functions for moreefficient operation of the MAC device. Furthermore, as described ingreater detail herein, the switching from one of the input data streamsIN₁ through IN_(X) to another of the input data streams IN₁ throughIN_(X) that are associated with PMD interface inputs can be implementedvery rapidly (e.g., less than 100 nanoseconds) based on maintaining theinput data streams IN₁ through IN_(X) on the PCS interface, thusproviding the switching absent a need for retraining of the associatedlinks (e.g., KR links) to a different PCS interface.

Additionally, the network PHY switch system 50 includes a fault detector62 that is configured to detect link faults associated with the datastream OUT_(M) that is provided from the multiplexer 52. As an example,the link faults can correspond to a loss of signal fault, a loss of KRblock lock fault, a KR 64/66B decoding error fault, or a variety ofother faults. The fault detector 62 can, in response to detecting afault associated with the data stream OUT_(M), provide a fault signalFLT to the switching controller 54. In response to the fault signal FLT,the switching controller 54 can change the state of the select signalSEL to switch from a current one of the input data streams IN₁ throughIN_(X) that has a detected fault associated with it to a second one ofthe input data streams IN₁ through IN_(X). As an example, the switchingcontroller 54 can provide the switching from the faulted one of theinput data streams IN₁ through IN_(X) to another of the input datastreams IN₁ through IN_(X) based on a programmable condition, such asdetected by the data detector 58. In other examples, dummy data can beswitched to dummy data DD in response to the fault signal FLT.Therefore, the trigger signal TRG can also provide an indication of whento change the state of the selection signal SEL in response to the faultsignal FLT, such as based on KR fault signaling, between packets,immediately, or in response to any of a variety of other conditions.

FIG. 3 illustrates an example of a routing device 100. The routingdevice 100 can correspond to a routing device provided in a PHY deviceand configured to route each of a plurality of sets of input datastreams to a respective one of a plurality of outputs. In the example ofFIG. 3, a plurality N of sets of input data streams are provided to therouting device 100, with each of the plurality N of data streamsincluding a plurality X of data streams, where N and X are each positiveintegers. While the example of FIG. 3 demonstrates that each of the Nsets of data streams includes X data streams, it is to be understoodthat each of the N sets of data streams can include a different numberof data streams relative to each other, and are not limited to having anequal number of data streams (e.g., a quantity X). Thus, the datastreams are demonstrated in the example of FIG. 3 as including a firstset of data streams IN₁ _(_) ₁ through IN₁ _(_) _(X) through an Nth setof data streams IN_(N) _(_) ₁ through IN_(N) _(_) _(X). As an example,each of the N sets of data streams IN₁ through IN_(X) can correspond toan input port associated with the routing device 100. As anotherexample, the routing device 100 can correspond to a single port of alarger routing system, such that the routing device 100 can correspondto one of a plurality of ports of the larger routing system.

The routing device 100 includes a plurality N of network PHY switchsystems 102, each corresponding to a given one of the N sets of the datastreams IN₁ through IN_(X). Each of the network PHY switch systems 102provides a respective output data stream, demonstrated as OUT₁ throughOUT_(N), respectively. Each of the network PHY switch systems 102 can beconfigured substantially similar to the network PHY switch system 50 inthe example of FIG. 2. Therefore, each of the network PHY switch systems102 can include a multiplexer 52, a switching controller 54, a CTC FIFO56, a data detector 58, a data mask component 60, and/or a faultdetector 62 to implement PHY switching of a given one of the datastreams IN₁ through IN_(X) to the respective output stream OUT, similarto as described previously. As an example, the routing device 100 caninclude a plurality of switch controllers 54 that are each associatedwith a respective one of the network PHY switch systems 102, or caninclude a single switch controller 54 that is configured to receive aplurality of switching control signals SW_(CTL) and to provide aplurality of selection signals SEL to a respective plurality ofmultiplexers 52 associated with the respective network PHY switchsystems 102.

As an example, the routing device 100 can be implemented in an Ethernetrouting system, such as in a redundant crosspoint routing system.Additionally, the routing device 100 can include a plurality ofadditional circuit devices, such as an MDIO to control the switching ofthe N sets of data streams IN₁ through IN_(X) to the respective outputstreams OUT₁ through OUT_(N). Furthermore, the routing device 100 can beconfigured in a crosspoint mode, such that a given data stream IN₁through IN_(X) can be switched as an output OUT from a different one ofthe network PHY switch systems 102, or in a retime mode, such that agiven one of the output streams OUT₁ through OUT_(N) can be provided asone of the input data streams IN₁ through IN_(X) in one of the networkPHY switch systems 102. Accordingly, the routing device 100 can beconfigured in a variety of ways.

FIG. 4 illustrates an example of a crosspoint routing system 150. As anexample, the crosspoint routing system 150 can correspond to a10GBase-KR network routing system. The crosspoint routing system 150includes a plurality of ports 152, demonstrated as four ports PORT 1,PORT 2, PORT 3, and PORT 4 in the example of FIG. 4. Each of the ports152 receives an input, demonstrated as IN_(P1), IN_(P2), IN_(P3), andIN_(P4), respectively, and provides an output, demonstrated as OUT_(P1),OUT_(P2), OUT_(P3), and OUT_(P4), respectively. As an example, each ofthe ports 152 can be coupled to a device on an associated network (e.g.,computer, server, or other routing device). Each of the ports 152 arecoupled to a common backplane 154, such as based on copper or otherelectrically conductive material, such as in a KR network configuration.

Each of the ports 152 includes a MAC device 156 and a PHY device 158.The MAC device 156 receives the respective input INP and provides therespective output OUT_(P), such as from and to a respective device onthe associated network. The MAC device 156 is configured to provide MACtransmit signals M_(TX) to the respective PHY device 158, and to receiverespective MAC receive signals M_(RX) from the respective PHY device158. Similarly, the PHY device 158 is configured to provide PHY transmitsignals P_(TX) to the backplane 154 and to receive PHY receive signalsP_(RX) from the backplane 154. In the example of FIG. 4, each of the PHYdevices 158 in each of the respective ports 152 includes a set ofnetwork PHY switch systems 160 that are configured to switch one or moreof the MAC transmit signals M_(TX) and/or one or more of the PHY receivesignals P_(RX) to one of a plurality of outputs, such as associated withthe associated MAC receive signals M_(RX) and/or the PHY transmitsignals P_(TX). As described herein, the terms “receive” and “transmit”are used with respect to the respective device of which they areassociated. For example, the MAC transmit signals M_(TX) are transmittedfrom the MAC device 156 and the MAC receive signals are received by theMAC device 156, and the PHY transmit signals P_(TX) are transmitted fromthe PHY device 158 and the PHY receive signals are received by the PHYdevice 158.

As an example, the PHY device 158 associated with each of the ports 152can include a plurality of network PHY switch systems 160 that are eachassociated with a given output of the PHY device 158. Each of thenetwork PHY switch systems 160 can be configured substantially similarto the network PHY switch system 50 in the example of FIG. 2. Forexample, the PHY device 158 can include at least one output associatedwith a respective at least one of the MAC receive signals M_(RX) and atleast one output associated with a respective at least one of the PHYtransmit signals Pr_(TX). Therefore, the network PHY device 158 in agiven one of the ports 152 can be configured to switch a given one ofthe MAC transmit signals M_(TX) or a given one of the PHY receivesignals P_(RX) to any of the outputs of the PHY device 158 in any of avariety of switching modes (e.g., mission mode, crosspoint mode, and/orretime mode). Thus, a given one of the MAC transmit signals M_(TX) or agiven one of the PHY receive signals P_(RX) can be provided as one ofthe MAC receive signals M_(RX) that is provided to the respective MACdevice 156 or as one of the PHY transmit signals Pr_(TX) that isprovided to the backplane 154.

FIG. 5 illustrates an example of a PHY device 200. The PHY device 200can correspond to a PHY device 158 associated with a given one of theports 152 in the crosspoint routing system 150 in the example of FIG. 4.Therefore, reference is to be made to the example of FIG. 4 in thefollowing description of the example of FIG. 5 for additional context.

The PHY device 200 includes a MAC interface 202 and a physical mediumdependent (PMD) interface 204. The MAC interface 202 includes a firstMAC interface input 206 and a second MAC interface input 208,demonstrated in the example of FIG. 5 as INPUT A and INPUT B,respectively, and includes a first MAC interface output 210 and a secondMAC interface output 212, demonstrated in the example of FIG. 5 asOUTPUT A and OUTPUT B. The first and second MAC interface inputs 206 and208 are configured to receive a MAC transmit signal M_(TX) _(_) _(A) anda MAC transmit signal M_(TX) _(_) _(B), respectively, from a MAC device(e.g., the MAC device 156 in a given port 152), and the first and secondMAC interface outputs 210 and 212 are configured to transmit a MACreceive signal M_(RX) _(_) _(A) and a MAC receive signal M_(RX) _(_)_(B), respectively, to the MAC device. As an example, the MAC interface202 can be configured to operate via a serializer/deserializer (SerDes)at a first data rate. For example, the MAC interface 202 can operate viaa 10 Attachment Unit Interface (XAUI), and thus to provide each of theMAC receive signals M_(RX) _(_) _(A) and M_(RX) _(_) _(B) and to receiveeach of the MAC transmit signals M_(TX) _(_) _(A) and M_(TX) _(_) _(B)as four differential pairs.

Similarly, the PMD interface 204 includes a first PMD interface receiver214 and a second PMD interface receiver 216, demonstrated in the exampleof FIG. 5 as RECEIVER A and RECEIVER B, respectively, and includes afirst PMD interface transmitter 218 and a second PMD interfacetransmitter 220, demonstrated in the example of FIG. 5 as TRANSMITTER Aand TRANSMITTER B. The first and second PMD interface receivers 214 and216 are configured to receive a PHY receive signal P_(RX) _(_) _(A) anda PHY receive signal P_(RX) _(_) _(B), respectively, from a backplane(e.g., the backplane 154), and the first and second PMD interfacetransmitter 218 and 220 are configured to transmit a PHY transmit signalP_(TX) _(_) _(A) and a PHY transmit signal P_(TX) _(_) _(B),respectively, to the backplane. As an example, the PMD interface 204 canbe configured to operate via a SerDes at a second data rate that isfaster than the first data rate associated with the MAC interface 202.For example, the PMD interface 204 can operate via XGMII, and thus toprovide each of the PHY transmit signals P_(TX) _(_) _(A) and P_(TX)_(_) _(B) and to receive each of the PHY receive signals P_(RX) _(_)_(A) and P_(RX) _(_) _(B) as single conductor serial signals.

In the example of FIG. 5, the first MAC interface output 210 includes anetwork PHY switch system 222, demonstrated as SWITCH OA, and the secondMAC interface output 212 includes a network PHY switch system 224,demonstrated as SWITCH OB. Similarly, the first PMD interfacetransmitter 218 includes a network PHY switch system 226, demonstratedas SWITCH TA, and the second PMD interface transmitter 220 includes anetwork PHY switch system 228, demonstrated as SWITCH TB. As an example,each of the network PHY switch systems 222, 224, 226, and 228 can beconfigured substantially similar to the network PHY switch system 50 inthe example of FIG. 2. For example, each of the network PHY switchsystems 222, 224, 226, and 228 can be configured to receive at amultiplexer (e.g., the multiplexer 52) each of the MAC transmit signalsM_(TX) _(_) _(A) and M_(TX) _(_) _(B) and the PHY receive signals P_(RX)_(_) _(A) and P_(RX) _(_) _(B) as respective separate input data streams(e.g., corresponding to the input data streams IN₁ through IN_(X)).Thus, the network PHY switch systems 222 and 224 can output a datastream that is converted from the second data rate (e.g., in a missionor crosspoint mode) to the first data rate to provide the respective MACreceive signals M_(RX) _(_) _(A) and M_(RX) _(_) _(B) as one of the PHYreceive signals P_(RX) _(_) _(A) and P_(RX) _(_) _(B), as demonstratedby the arrow 230. Similarly, the network PHY switch systems 226 and 228can output a data stream that is converted from the first data rate tothe second data rate (e.g., in a mission or crosspoint mode) to providethe respective PHY transmit signals P_(TX) _(_) _(A) and P_(TX) _(_)_(B) as one of the MAC transmit signals M_(TX) _(_) _(A) and M_(TX) _(_)_(B), as demonstrated by the arrow 230.

For example, the network PHY switch system 222 can provide the MACreceive signal M_(RX) _(_) _(A) as corresponding to one of the MACtransmit signals M_(TX) _(_) _(A) and M_(TX) _(_) _(B) and PHY receivesignals P_(RX) _(_) _(A) and P_(RX) _(_) _(B), and the network PHYswitch system 224 can provide the MAC receive signal M_(RX) _(_) _(B) ascorresponding to one of the MAC transmit signals M_(TX) _(_) _(A) andM_(TX) _(_) _(B) and PHY receive signals P_(RX) _(_) _(A) and P_(RX)_(_) _(B). Similarly, the network PHY switch system 226 can provide thePHY transmit signal P_(TX) _(_) _(A) as corresponding to one of the MACtransmit signals M_(TX) _(_) _(A) and M_(TX) _(_) _(B) and PHY receivesignals P_(RX) _(_) _(A) and P_(RX) _(_) _(B), and the network PHYswitch system 224 can provide the PHY transmit signal P_(TX) _(_) _(B)as corresponding to one of the MAC transmit signals M_(TX) _(_) _(A) andM_(TX) _(_) _(B) and PHY receive signals P_(RX) _(_) _(A) and P_(RX)_(_) _(B). Therefore, each of the network PHY switch systems 222, 224,226, and 228 can provide selective switching of any of the inputs to thePHY device 200 as the respective outputs corresponding to the MACreceive signals M_(RX) _(_) _(A) and M_(RX) _(_) _(B) and the PHYtransmit signals P_(TX) _(_) _(A) and P_(TX) _(_) _(B) in a variety ofmodes.

FIG. 6 illustrates yet another example of a network PHY switch system250. The network PHY switch system 250 can correspond to the network PHYswitch system 222 in the example of FIG. 5. Thus, the network PHY switchsystem 250 can be implemented in the PHY device 200, such as in thecrosspoint routing system 150 in the example of FIG. 4. In the exampleof FIG. 6, the network PHY switch system 250 is configured to providethe MAC receive signal M_(RX) _(_) _(A) as an output data stream thatcorresponds to a given one of a plurality of input data streamscorresponding to the MAC transmit signal M_(TX) _(_) _(A), the MACtransmit signal M_(TX) _(_) _(B), the PHY receive signal P_(RX) _(_)_(A), and the PHY receive signal P_(RX) _(_) _(B). The selection of thegiven one of the input data streams M_(TX) _(_) _(A), M_(TX) _(_) _(B),P_(RX) _(_) _(A), and P_(RX) _(_) _(B) can be set by a switching controlsignal SW_(CTL) _(_) _(OA), such as provided from an external circuit ordevice (e.g., an MDIO device).

In the example of FIG. 6, the network PHY switch system 250 includes amultiplexer 252, a data detector 254, and a switching controller 256.The multiplexer 252 is configured to receive the input data streams andto provide a given one of the input data streams M_(TX) _(_) _(A),M_(TX) _(_) _(B), P_(RX) _(_) _(A), and P_(RX) _(_) _(B) at an outputbased on the switching controller 256 (e.g., based on a state of aselection signal SEL provided by the switching controller 256). As anexample, the switching controller 256 can control which of the inputdata streams M_(TX) _(_) _(A), M_(TX) _(_) _(B), P_(RX) _(_) _(A), andP_(RX) _(_) _(B) in response to the switching control signal SW_(CTL)_(_) _(OA). The data detector 254 is configured to monitor the given oneof the data streams M_(TX) _(_) _(A), M_(TX) _(_) _(B), P_(RX) _(_)_(A), and P_(RX) _(_) _(B) that is provided at the output of themultiplexer 252, and can provide an indication (e.g., via the triggersignal TRG) to the switching controller 256 of the occurrence of apredetermined condition (e.g., end of a packet or another condition,such as a fault condition) associated with the given one of the datastreams M_(TX) _(_) _(A), M_(TX) _(_) _(B), P_(RX) _(_) _(A), or P_(RX)_(_) _(B) that is provided at the output of the multiplexer 252. As anexample, the indication can be the trigger signal TRG that is indicativeof the predetermined condition. Thus, the switching controller 256 canbe programmed to switch from one of the input data streams M_(TX) _(_)_(A), M_(TX) _(_) _(B), P_(RX) _(_) _(A), and P_(RX) _(_) _(B) to asecond of the input data streams M_(TX) _(_) _(A), M_(TX) _(_) _(B),P_(RX) _(_) _(A), and P_(RX) _(_) _(B) based on occurrence of thepredetermined condition, such as to mitigate packet corruption of thedata in the output data stream M_(RX) _(_) _(A).

Therefore, the network PHY switch system 250 is configured to provideswitching between the input data streams M_(TX) _(_) _(A), M_(TX) _(_)_(B), P_(RX) _(_) _(A), and P_(RX) _(_) _(B) in a variety of modes. Forexample, the network PHY switch system 250 can provide the input datastream P_(RX) _(_) _(A) as the output data stream M_(RX) _(_) _(A) basedon a first state of the selection signal SEL in a mission mode, and canprovide the input data stream P_(RX) _(_) _(B) as the output data streamM_(RX) _(_) _(A) based on a second state of the selection signal SEL ina crosspoint mode. As another example, the network PHY switch system 250can provide the input data stream M_(TX) _(_) _(A) as the output datastream M_(RX) _(_) _(A) based on a third state of the selection signalSEL in a first retime mode, and can provide the input data stream M_(TX)_(_) _(B) as the output data stream M_(RX) _(_) _(A) based on a fourthstate of the selection signal SEL in a second retime mode. In the retimemodes, the associated PHY device (e.g., the PHY device 200) thatincludes the network PHY switch system 250 does not need to convert thedata rates of the respective input data streams M_(TX) _(_) _(A) andM_(TX) _(_) _(B), and can thus provide the switching between therespective input data streams M_(TX) _(_) _(A) and M_(TX) _(_) _(B) morerapidly.

FIG. 7 illustrates a further example of a network PHY switch system 300.The network PHY switch system 300 can correspond to the network PHYswitch system 226 in the example of FIG. 5. Thus, the network PHY switchsystem 300 can be implemented in the PHY device 200, such as in thecrosspoint routing system 150 in the example of FIG. 4. In the exampleof FIG. 7, the network PHY switch system 300 is configured to providethe PHY transmit signal P_(TX) _(_) _(A) as an output data stream thatcorresponds to a given one of a plurality of input data streamscorresponding to the MAC transmit signal M_(TX) _(_) _(A), the MACtransmit signal M_(TX) _(_) _(B), the PHY receive signal P_(RX) _(_)_(A), and the PHY receive signal P_(RX) _(_) _(B). The selection of thegiven one of the input data streams M_(TX) _(_) _(A), M_(TX) _(_) _(B),P_(RX) _(_) _(A), and P_(RX) _(_) _(B) can be set by a switching controlsignal SW_(CTL) _(_) _(TA), such as provided from an external circuit ordevice (e.g., an MDIO device).

In the example of FIG. 7, the network PHY switch system 300 includes amultiplexer 302, a data detector 304, and a switching controller 306.The multiplexer 302 is configured to receive the input data streams andto provide a given one of the input data streams M_(TX) _(_) _(A),M_(TX) _(_) _(B), P_(RX) _(_) _(A), and P_(RX) _(_) _(B) at an outputbased on the switching controller 306 (e.g., based on a state of aselection signal SEL provided by the switching controller 306). As anexample, the switching controller 306 can control which of the inputdata streams M_(TX) _(_) _(A), M_(TX) _(_) _(B), P_(RX) _(_) _(A), andP_(RX) _(_) _(B) in response to the switching control signal SW_(CTL)_(_) _(TA). The data detector 304 is configured to monitor the given oneof the data streams M_(TX) _(_) _(A), M_(TX) _(_) _(B), P_(RX) _(_)_(A), and P_(RX) _(_) _(B) that is provided at the output of themultiplexer 302, and can provide an indication (e.g., via the triggersignal TRG) to the switching controller 306 of the occurrence of apredetermined condition (e.g., end of a packet or another condition,such as a fault condition) associated with the given one of the datastreams M_(TX) _(_) _(A), N_(TX) _(_) _(B), P_(RX) _(_) _(A), or P_(RX)_(_) _(B) at the output of the multiplexer 302. As an example, theindication can be the trigger signal TRG that is indicative of thepredetermined condition. Thus, the switching controller 306 can beprogrammed to switch from one of the input data streams M_(TX) _(_)_(A), M_(TX) _(_) _(B), P_(RX) _(_) _(A), and P_(RX) _(_) _(B) to asecond of the input data streams M_(Tx A), M_(TX) _(_) _(B), P_(RX) _(_)_(A), and P_(RX) _(_) _(B) based on occurrence of the predeterminedcondition, such as to mitigate packet corruption of the data in theoutput data stream P_(TX) _(_) _(A).

Therefore, the network PHY switch system 300 is configured to provideswitching between the input data streams M_(TX) _(_) _(A), M_(TX) _(_)_(B), P_(RX) _(_) _(A), and P_(RX) _(_) _(B) in a variety of modes. Forexample, the network PHY switch system 300 can provide the input datastream M_(TX) _(_) _(A) as the output data stream P_(TX) _(_) _(A) basedon a first state of the selection signal SEL in a mission mode, and canprovide the input data stream M_(TX) _(_) _(B) as the output data streamP_(TX) _(_) _(A) based on a second state of the selection signal SEL ina crosspoint mode. As another example, the network PHY switch system 300can provide the input data stream P_(RX) _(_) _(A) as the output datastream P_(TX) _(_) _(A) based on a third state of the selection signalSEL in a first retime mode, and can provide the input data stream P_(RX)_(_) _(B) as the output data stream P_(TX) _(_) _(A) based on a fourthstate of the selection signal SEL in a second retime mode. In the retimemodes, the associated PHY device (e.g., the PHY device 200) thatincludes the network PHY switch system 300 does not need to convert thedata rates of the respective input data streams P_(RX) _(_) _(A) andP_(RX) _(_) _(B), and can thus provide the switching between therespective input data streams P_(RX) _(_) _(A) and P_(RX) _(_) _(B) morerapidly. For example, in the example of FIG. 7, in the retime modes, theKR physical link remains intact in providing one of the input datastreams P_(RX) _(_) _(A) and P_(RX) _(_) _(B) as the output data streamP_(TX) _(_) _(A), such that KR link training is not re-initiated as aresult of switching.

In view of the foregoing structural and functional features describedabove, a method in accordance with various aspects of the presentinvention will be better appreciated with reference to FIG. 8. While,for purposes of simplicity of explanation, the method of FIG. 8 is shownand described as executing serially, it is to be understood andappreciated that the present invention is not limited by the illustratedorder, as some aspects could, in accordance with the present invention,occur in different orders and/or concurrently with other aspects fromthat shown and described herein. Moreover, not all illustrated featuresmay be required to implement a method in accordance with an aspect ofthe present invention.

FIG. 8 illustrates an example of a method 350 for switching from a firstdata stream (e.g., a first of the input data streams IN₁ through IN_(X))to a second data stream (e.g., a second of the input data streams IN₁through IN_(X)) in a PHY device (e.g., the PHY device 200) of a networkdevice (e.g., the crosspoint routing system 150). At 352, a selectionsignal (e.g., the selection signal SEL) is provided in a first state toselect the first data stream that is input to the PHY device to beoutput from a multiplexer (e.g., the multiplexer 52). At 354, aswitching control signal (e.g., the switching control signal SW_(CTL))that indicates a command to switch from the first data stream to thesecond data stream is received. At 356, an output of a FIFO (e.g., theCTC FIFO 56) buffer is monitored to detect a predetermined condition(e.g., an end of a packet) associated with the first data stream. At358, a trigger signal (e.g., the trigger signal TRG) is provided inresponse to an occurrence of the predetermined condition. At 360, theselection signal is provided in a second state to switch the input tothe PHY device from the first data stream to the second data stream tobe output from the multiplexer.

What have been described above are examples of the invention. It is, ofcourse, not possible to describe every conceivable combination ofcomponents or method for purposes of describing the invention, but oneof ordinary skill in the art will recognize that many furthercombinations and permutations of the invention are possible.Accordingly, the invention is intended to embrace all such alterations,modifications, and variations that fall within the scope of thisapplication, including the appended claims.

What is claimed is:
 1. A network physical link (PHY) switch systemcomprising: a multiplexer configured to output a first data stream of aplurality of data streams that are input to a PHY device in response toa first state of a selection signal; a data detector configured tomonitor the first data stream and to provide a trigger signal inresponse to detecting an occurrence of a predetermined conditionassociated with the first data stream; and a switching controllerconfigured to provide the selection signal in one of the first state anda second state, and, in response to receiving a switching command signalthat indicates a command to switch from the first data stream to asecond data stream of the plurality of data streams, is configured tomonitor the data detector for the trigger signal and to change theselection signal from the first state to the second state in response toreceiving the trigger signal to switch from the first data stream to thesecond data stream, wherein the first data stream and the second datastream correspond to one of a plurality of MAC transmit signals providedto the PHY device from a media access control (MAC) device or one of aplurality of PHY receive signals provided to the PHY device from abackplane to which the PHY device is connected.
 2. The system of claim1, further comprising a data mask component configured to discard thefirst data stream and to insert dummy data in place of the discardedfirst data stream in response to the trigger signal, wherein the datadetector is further configured to deactivate the trigger signal inresponse to a predetermined condition associated with the second datastream to enable the second data stream to pass through the data maskcomponent.
 3. The system of claim 1, wherein the predetermined conditionassociated with the first data stream corresponds to an end of a packetassociated with the first data stream.
 4. The system of claim 1, furthercomprising a clock tolerance compensation (CTC) first-in-first-out(FIFO) buffer coupled to the output of the multiplexer, the CTC FIFObeing configured to buffer the first data stream during the first stateof the selection signal and to buffer the second data stream during thesecond state of the selection signal.
 5. The system of claim 1, furthercomprising a fault detection component configured to detect a link faultassociated with the first data stream and to indicate the link fault tothe switching controller to switch from the first data stream to thesecond data stream via the selection signal.
 6. An Ethernet routingsystem comprising the network PHY switch system of claim
 1. 7. Acrosspoint routing system that includes a plurality of the network PHYswitch system of claim 1, the crosspoint routing system comprising: aplurality of ports coupled to a backplane, each of the plurality ofports comprising a media access control (MAC) device and the PHY device,the PHY device comprising: a MAC interface comprising a plurality of MACinterface outputs configured to transmit a respective plurality of MACreceive signals to the MAC device, each of the plurality of MACinterface outputs comprising the at least one of the network PHY switchsystems; and a physical medium dependent (PMD) interface comprising aplurality of PMD interface outputs configured to transmit a respectiveplurality of PHY transmit signals to the backplane, each of theplurality of PMD interface outputs comprising another of the network PHYswitch systems.
 8. The crosspoint routing system of claim 7, wherein theMAC interface further comprises a plurality of MAC interface inputsconfigured to receive the plurality of MAC transmit signals from the MACdevice, and wherein the PMD interface further comprises a plurality ofPMD interface inputs configured to receive the plurality of PHY receivesignals from the backplane.
 9. The crosspoint routing system of claim 8,wherein the multiplexer associated with each of the plurality of MACinterface outputs is configured to output the respective one of theplurality of MAC receive signals as one of the plurality of MAC transmitsignals or one of the plurality of PHY receive signals in response tothe selection signal, and wherein the multiplexer associated with eachof the plurality of PMD interface outputs is configured to output therespective one of the plurality of PHY transmit signals as one of theplurality of MAC transmit signals or one of the plurality of PHY receivesignals in response to the selection signal.
 10. The crosspoint routingsystem of claim 7, wherein the MAC interface is configured to receivethe plurality of MAC transmit signals and to transmit the plurality ofMAC receive signals at a first data rate, and wherein the PMD interfaceis configured to receive the plurality of PHY receive signals and totransmit the plurality of PHY transmit signals at a second data ratethat is greater than the first data rate.
 11. The crosspoint routingsystem of claim 10, wherein the multiplexer associated with each of theplurality of PMD interface outputs is configured to output therespective one of the plurality of PHY transmit signals as one of theplurality of PHY receive signals in response to the selection signal ina retime mode absent a change of the respective one of the plurality ofPHY receive signals from the second data rate to the first data rate.12. A method for switching from a first data stream to a second datastream in a physical link (PHY) device of a network device, the methodcomprising: providing a selection signal in a first state to select thefirst data stream that is input to the PHY device to be output from amultiplexer; receiving a switching control signal that indicates acommand to switch from the first data stream to the second data stream;monitoring an output of a first-in-first-out (FIFO) buffer to detect apredetermined condition associated with the first data stream; providinga trigger signal in response to detecting the predetermined conditionassociated with the first data stream; and providing the selectionsignal in a second state to switch the input to the PHY device from thefirst data stream to the second data stream to be output from themultiplexer, wherein the first data stream and the second data streamcorrespond to one of a plurality of MAC transmit signals provided to thePHY device from a media access control (MAC) device or one of aplurality of PHY receive signals provided to the PHY device from abackplane to which the PHY device is connected.
 13. The method of claim12, further comprising: replacing data at the output of the FIFO bufferwith dummy data in response to the trigger signal; monitoring the outputof the FIFO buffer to detect a beginning of the second data stream; anddeactivating the trigger signal to provide the second data stream froman input associated with the PHY device to be output from themultiplexer in response to detecting the beginning of the second datastream at the output of the FIFO buffer.
 14. The method of claim 12,wherein monitoring the output of the FIFO buffer comprises monitoringthe output of the FIFO buffer to detect an end of a packet associatedwith the first data stream.
 15. A crosspoint routing system comprising aphysical link (PHY) device, the PHY device comprising: a media accesscontrol (MAC) interface comprising a MAC interface output configured totransmit a MAC receive signal corresponding to one of a plurality of MACtransmit signals and a plurality of PHY receive signals to a MAC devicevia a MAC interface switch, and further comprising a MAC interface inputconfigured to receive the plurality of MAC transmit signals from the MACdevice; and a physical medium dependent (PMD) interface comprising a PMDinterface output configured to transmit a PHY transmit signalcorresponding to one of the plurality of MAC transmit signals and theplurality of PHY receive signals to a backplane via a PMD interfaceswitch, and further comprising a PMD interface input configured toreceive the plurality of PHY receive signals from the backplane, whereinthe PHY device is configured to switch from a first data stream to asecond data stream, wherein the first data stream and the second datastream correspond to one of the plurality of MAC transmit signals or oneof a plurality of PHY receive signals.
 16. The system of claim 15,wherein each of the MAC interface switch and the PMD interface switchcomprises: a multiplexer configured to output the first data stream of aplurality of data streams that are input to the PHY device in responseto a first state of a selection signal; a data detector configured tomonitor the first data stream and to provide a trigger signal inresponse to detecting a predetermined condition associated with thefirst data stream; and a switching controller configured to provide theselection signal in one of the first state and a second state, and, inresponse to receiving a switching command signal that indicates acommand to switch from the first data stream to the second data streamof the plurality of data streams, is configured to monitor the datadetector for the trigger signal and to change the selection signal fromthe first state to the second state in response to receiving the triggersignal to switch from the first data stream to the second data stream.17. The system of claim 16, further comprising a data mask componentconfigured to discard the first data stream and to insert dummy data inplace of the discarded first data stream in response to the triggersignal, wherein the data detector is further configured to deactivatethe trigger signal in response to a predetermined condition associatedwith the second data stream to enable the second data stream to passthrough the data mask component.
 18. The system of claim 15, wherein theMAC interface is configured to receive the plurality of MAC transmitsignals and to transmit the MAC receive signal at a first data rate, andwherein the PMD interface is configured to receive the plurality of PHYreceive signals and to transmit the PHY transmit signal at a second datarate that is greater than the first data rate.
 19. The system of claim18, wherein the PMD interface switch is configured to output the PHYtransmit signal corresponding to a first PHY receive signal of pluralityof the PHY receive signals in a retime mode absent a change of the firstPHY receive signal from the second data rate to the first data rate.